Route /api/auth through the same origin in both dev and prod so
cookies stay first-party and the browser and React Router SSR share
one auth surface.
- Vite dev server proxies /api/auth to the Convex HTTP site.
- Better Auth uses secure cookies when the site URL is https.
- Add docs/auth-proxy.md documenting the required production ingress
(Caddy/Traefik) and Convex SITE_URL / CONVEX_SITE_URL setup.
- Register SITE_URL, NATIVE_APP_URL, CONVEX_SITE_URL, FLUE_DB_TOKEN in
convex.config.ts so the generated server.js exposes a typed env object.
- Rewrite auth.ts to consume @code/env/convex and tighten the
getCurrentUser handler.
- Refresh the backend README to describe the control-plane role and
generated-file policy.
